How to deal with this ex...

Husband and I have been together a couple years and have a baby together, own a house ect...when he was younger he got a girl knocked up that he was messing around with and they lost the baby early on then broke up a couple months later because she was going crazy on him and pushing him to get her pregnant when he wasn't ready and didn't even mean to in the first place then tried overdosing herself. Well fast forward to us, our child was born and a week or two after his ex tried to add me on Facebook, I immediately told him and he told me not to because she's crazy. So I denied her. Shortly after she sent him a Facebook message saying she still cares about him, misses him, and hopes he has a great life...she has a boyfriend and a child with him. My husband deleted the message...then SHE the ex also deleted a couple of our mutual friends which included a child on Facebook because they hung out with me and wouldn't give her info or pics of our child. My husband keeps telling me to let it go because she's crazy and dumb...I'm trying my hardest to let it go but it's bothering me a lot...I can't even use our family photo as my profile pic because he doesn't want her to see our baby...I can't block her because she's had her friends try adding me to get pics of our baby and I only knew they were her friends because I checked their friends list....I'm having a really hard time holding my tongue and the only thing that's keeping me from losing it is my husband telling me it will get worse if I say anything to her
EDIT: I must not have been clear my husband didn't delete anyone, he hasn't done anything besides delete the message she sent him and no he doesn't want her getting our baby's photos. I don't think that makes him crazy.